////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2009 Daniel F. Hanson
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
////////////////////////////////////////////////////////////////////////////////

using System.Collections.Generic;

namespace SilverLua.Compiler
{
   internal class BlockScope
   {
      private Dictionary<string, Symbol> _values = new Dictionary<string, Symbol>();
      private BlockScope _parentBlock;
      
      internal BlockScope()
      {
         _parentBlock = null;
      }
      
      internal BlockScope(BlockScope parent)
      {
         _parentBlock = parent;
      }
      
      internal Symbol AddLocal(ChunkScope chunk, string name, int index)
      {
         Symbol symbol = new Symbol(chunk, name, OperandType.Value, index);
         _values[name] = symbol;
         return symbol;
      }
      
      internal bool ResolveName(string name, out Symbol symbol)
      {
         return _values.TryGetValue(name, out symbol) ||
                _parentBlock != null && _parentBlock.ResolveName(name, out symbol);
      }
   }
}
